For the purposes of this invention, the term “food supports” refers to all slide-in elements which are customarily used in baking ovens, such as baking sheets, shelves, baking trays, drip pans, etc.
Furthermore, according to the invention, the term “food supports” is understood as meaning securing devices for aforementioned oven slide-in elements, such as for example frames into which such slide-in elements can be inserted or onto which they can be placed. For the purposes of the invention, a food support consequently does not necessarily have to have a resting surface for the actual food but may also serve simply for fastening or holding such a supporting surface, such as a baking sheet.
The terms “front” and “rear” used here with respect to the baking oven, the food support or telescopic guides refer to a region which, in the case of the oven, is directed toward the opening of the oven (front) or toward the rear side of the oven. A customary baking oven comprises a housing with oven outer walls and a muffle arranged in it with muffle side walls, upper and lower muffle walls and a muffle rear wall, the space inside the muffle representing the actual cooking space of the oven.
Extraction systems for food supports in a baking oven are known in a wide variety of forms and are constantly undergoing further development and improvement. In the case of simple known baking ovens, the food support is guided in grooves which are formed at various heights or levels in the muffle side wall. The sliding behavior of the food supports in such grooves depends on the surface finish of the areas sliding on one another, and the loading of the food support, and is comparatively poor. In the case of other systems, instead of grooves there are grids attached to the muffle side walls with horizontal bars, on which the food supports are guided. On account of the smaller supporting surface, here the sliding behavior is somewhat improved in comparison with grooves. Both systems have the disadvantage that the food support can only be pulled out of the oven to a certain extent without tipping downward or having to be supported at the front. Although the upper groove limitations, or further horizontal grid bars provided a small distance above the food support can support the food support, preventing it from tipping, to a certain pulled-out extent, and so make it possible for it to be pulled out somewhat further, it is not possible in the case of such arrangements for the food support to be pulled out completely, to bring it in front of the muffle, without the food support having to be held by a person.
In the case of improved baking ovens, telescopic guides with in each case a stationary rail and one or more movable rails, which are mounted such that they can slide in the longitudinal direction in relation to the stationary rail and out of the oven, are provided on the muffle side wall or on a grid. A food support can be placed onto the movable rails, so that the food support can be pulled out of the oven by pulling out the telescopic guides. Furthermore, there is a known system with telescopic guides in which the food support resting on the movable telescopic guide rail can, after the movable rail has been pulled out fully as far as it will go, be pulled by a further distance, sliding on the rail, to bring it in front of the oven muffle. This allows the use of telescopic guides with only two rails, which is advantageous for cost reasons. A disadvantage is that it is absolutely necessary in the case of this system for the telescopic rails to be fastened to the side wall in the hot inner region of the oven muffle, in order that the food support can be placed onto the movable rail of the telescopic guide. On account of this mounting of the telescopic guides in the oven muffle, they are easily soiled by food, spattering or evaporating fat or other liquids. These soiling particles are deposited not only on the outer sides of the telescopic rails but also in their interior, to which access is difficult. Cleaning the interior of the telescopic guides, in particular cleaning the bearings, is virtually impossible, or only by placing the entire telescopic guides into a cleaning liquid or by pyrolytic cleaning at very high temperatures. In such cleaning, however, lubricating or sliding agent present in the bearings is in turn likewise removed at the same time, so that in this way the telescopic guides lose their good sliding properties after they have been cleaned a number of times.
A general advantage of telescopic guides in comparison with mounting of the food support in grooves or on wires of a framework is their smooth action, stability and security with respect to tipping of the food support when in a pulled-out position.